Optical Coherence Tomography Angiography of the Peripapillary Retina in Glaucoma

Progressive peripapillary capillary vessel density loss and long-term visual field progression in Normal tension glaucoma

PURPOSE

To explore the association between progressive peripapillary capillary vessel density (pcVD) reduction and the progression of visual field (VF) impairment in individuals with normal tension glaucoma (NTG).

DESIGN

Prospective cohort study.

METHODS

The study enrolled 110 participants with one eye each, totalling 110 NTG eyes. VF defects were evaluated using standard automated perimetry mean deviation (MD), while pcVD measurements were obtained using optical coherence tomography angiography throughout the follow-up period. Estimates of VF progression were determined by event-based and trend-based analyses. Fast VF progression was defined as an MD slope steeper than -0.5 dB/year, while the slow progression or stable VF was defined as an MD slope better or equal to -0.25 dB/year. Linear mixed-effects models were employed to analyse the rates of change in pcVD reduction and VF MD decline over time. Additionally, univariable and multivariable linear models were used to examine the relationship between pcVD changes and VF loss rates in NTG.

RESULTS

Slow VF progression or stable VF was observed in 45% of subjects, while 25% had moderate progression and 30% showed fast progression. Patients with VF progression exhibited faster rate of pcVD reduction in peripapillary global region (-0.73 ± 0.40%/year vs. -0.56 ± 0.35%/year, p = 0.022). Moreover, this rate positively correlated with VF MD decline in NTG (estimate 0.278, 95% CI 0.122-0.433, p = 0.001).

CONCLUSION

In individuals with NTG, faster VF progression was linked to a quicker reduction in pcVD, suggesting a positive correlation between pcVD decline and VF deterioration.

Longitudinal changes in optical coherence tomography angiography characteristics in normal-tension glaucoma with or without high myopia

PURPOSE

To evaluate the structural, microvascular, and functional progression of normal tension glaucoma (NTG) with or without high myopia by examining longitudinal changes in optical coherence tomography angiography (OCTA) and visual field (VF) parameters.

METHODS

We evaluated 61 NTG eyes and classified 25 of the eyes with axial lengths (ALs) of ≥26 mm as highly myopic. We assessed the rate of change in OCTA parameters, namely radial peripapillary capillary (RPC) vessel density (VD), parafovea VD, deep parafovea VD, retinal nerve fibre layer (RNFL) thickness, and ganglion cell complex thickness. We evaluated the correlation of the rate of change in OCTA parameters with VF loss and AL.

RESULTS

Among the 61 NTG eyes, rates of loss of RPC VD, parafovea VD, deep parafovea VD, and RNFL thickness were significantly different from zero despite the nonsignificant rate of change in VF mean deviation (MD). Changes in these OCTA parameters did not differ significantly in highly myopic NTG eyes. The rate of change in VF MD was significantly correlated with the rate of change in parafovea VD in highly myopic and non-highly myopic NTG eyes. In highly myopic NTG eyes, AL was negatively correlated with the rates of loss of RNFL thickness, VF MD, and VF PSD.

CONCLUSION

NTG eyes with a relatively stable VF exhibited loss of VD and RNFL thickness. VF progression in NTG was correlated with decreasing parafovea VD, indicating a structure-function correlation. Greater AL may indicate faster VF loss and RNFL thinning in highly myopic NTG eyes.

Dementia and glaucoma: Results from a Nationwide French Study between 2006 and 2018

PURPOSE

Glaucoma is the leading cause of irreversible blindness worldwide. The brain and eye share many characteristics, so the eye may provide an easy-access window on brain processes. The aim of the study was to evaluate the link between glaucoma as well as intraocular pressure (IOP)-lowering drops load and all-cause dementia.

METHODS

This was a nested case-control study based on the French national healthcare database from 1 January 2006 to 31 December 2018in individuals aged ≥60 years. We compared cases of incident all-cause dementia with 1:5 controls matched by date of case diagnosis (index date), age, sex, and income. We set a 5-year exposure to glaucoma period ending 2 years before the index date (lag-time period to avoid protopathic bias). The main outcome was glaucoma defined with hospitalization related to POAG and/or dispensations of IOP-lowering drops. The secondary outcome was the IOP-lowering drops load.

RESULTS

In total, 4810 incident all-cause dementia and 24 050 matched controls were analysed (median [IQR] age 82 [10] years; 66.6% women). The prevalence of glaucoma was 14.0% in controls and cases. Risk of all-cause dementia was not associated with glaucoma (crude OR, 1.02; 95% CI [0.93-1.11]; p = 0.7; adjusted OR, 0.99; 95% CI [0.91-1.09]; p = 0.9) or IOP-lowering drops load (p = 0.2).

CONCLUSION

The present study in general population ≥60 years old in France did not find any association between glaucoma and incident all-cause dementia.

Glaucomatous Focal Perfusion Loss in the Macula Measured by Optical Coherence Tomographic Angiography

PURPOSE

To measure low perfusion area (LPA) and focal perfusion loss (FPL) in the macula using optical coherence tomography (OCT) angiography (OCTA) for glaucoma.

DESIGN

Prospective, cross-sectional "case-control" comparison study.

METHODS

A total of 60 patients with primary open-angle glaucoma (POAG) and 37 healthy participants were analyzed. AngioVue 6 × 6-mm high-definition (400 × 400 transverse pixels) macular OCTA scans were performed on one eye of each participant. Flow signal was calculated using the split-spectrum amplitude-decorrelation angiography algorithm. En face ganglion cell layer plexus (GCLP) and superficial vascular complex (SVC) images were generated. Using custom software, vessel density (VD) maps were obtained by computing the fraction of area occupied by flow pixels after low-pass filtering by local averaging 41 × 41 pixels. LPA was defined by local VD below 0.5 percentile over a contiguous area above 98.5 percentile of the healthy reference population. The FPL was the percentage VD loss (relative to normal mean) integrated over the LPA.

RESULTS

Among patients with POAG, 30 had perimetric and 30 had preperimetric glaucoma. The LPAGCLP-VD was 0.16±0.38 mm2 in normal and 5.78±6.30 mm2 in glaucoma subjects (P < .001). The FPLGCLP-VD was 0.20%±0.47% in normal and 7.52%±8.84% in glaucoma subjects (P < .001). The perimetric glaucoma diagnostic accuracy, measured by the area under the receiver operating curve, was 0.993 for LPAGCLP-VD and 0.990 for FPLGCLP-VD. The sensitivities were, respectively, 96.7% and 93.3% at 95% specificity. The LPAGCLP-VD and FPLGCLP-VD had good repeatability (0.957 and 0.952 by intraclass correlation coefficient). Diagnostic accuracy was better than GCLP VD (AROC 0.950, sensitivity 83.3%) and OCT ganglion cell complex (GCC) thickness (AROC 0.927, sensitivity 80.0%) and GCC focal loss volume (AROC 0.957, sensitivity 80.0%). The LPAGCLP-VD and FPLGCLP-VD correlated well with central VF mean deviations (Pearson r = -0.716 and -0.705 respectively, both P < .001).

CONCLUSION

Assessment of macular FPL using OCTA is useful in evaluating glaucomatous damage.

Optical Coherence Tomography Advanced Parameters in Patients With Multiple Sclerosis: Ophthalmological and Neurological Assessments

PURPOSE

To evaluate ophthalmological, neurological, radiological, and laboratory data in patients with multiple sclerosis (MS) and to identify new ophthalmological factors that could be helpful as biomarkers of the disease, potentially leading to an earlier prediction of disease course and disability progression.

DESIGN

Retrospective, cross-sectional-study.

METHODS

Best-corrected visual acuity (BCVA), ophthalmological biomicroscopy of the anterior segment and fundus, structural optical coherence tomography (OCT) with retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC), and OCT angiography (OCTA) with vascular density (VD) were performed. The following clinical and neuro-radiological features were assessed: MS phenotype, disease duration, clinical severity, type of treatment, and T2-weighted lesion and T1-weighted Gd+ enhancing lesion number on the brain and spinal cord MRI.

RESULTS

One hundred and six patients (212 eyes) were analyzed. Sixty-six of them (62.2%) had MS and 40 (37.8%) were matched healthy controls (HCs). patients with MS showed lower RNFL, GCC, and VD in the radial peripapillary capillary plexus than controls in both eyes (P < .05). By Performing a logistic regression with a distinct MS outcome for both eyes, we were able to demonstrate that the value that was most predictive of MS was the average GCC thickness (P = .009). Regression analysis demonstrated that patients with a higher T2-weighted lesions showed a lower RNFL thickness value and reduced GCC and VD values than those with a low lesion load (P < .01 and P < .05, respectively). Similarly, relapsing MS patients showed lower RNFL values (P < .05).

CONCLUSIONS

Several OCT and OCTA-optic nerve parameters could be useful prognostic biomarkers for the MS disease course in clinical practice. However, it is necessary to do additional research with larger sample sizes in order to validate these findings.

Diagnostic ability of the combination of retinal microvasculature evaluation and static automated perimetry for early primary open-angle glaucoma

PURPOSE

To investigate the diagnostic ability of retinal superficial vasculature evaluation by optic coherence tomography angiography (OCTA) combined with visual field (VF) testing for early primary open-angle glaucoma (POAG).

PATIENTS AND METHODS

In this cross-sectional study, 84 participants were included, including 11 in the ocular hypertension (OHT) group, 11 in the preperimetric POAG (pre-POAG) group, 29 in the early POAG group and 33 in the control group. All participants underwent 6 × 6 mm2 scans of macula and optic nerved head by optic coherence tomography (OCT) and OCTA, along with white-on-white and blue-on-yellow VF testing by static automated perimetry. The ability of diagnosing early glaucoma by either various examinations separately or combination of examinations in both terms of function and structure was studied using the receiver operating characteristic (ROC) curve and the area under the curve (AUC).

RESULTS

The superficial retinal vessel densities (VD) in peri-nasal, para-temporal, peri-temporal and peri-inferior regions around the macula, as well as vessel area densities (VAD) in all peripapillary regions, were significantly different among the four groups, with lower VD or VAD in the early POAG patients compared to the normal individuals. The diagnostic ability of peripapillary superficial retinal VAD alone or VF testing alone was limited for early POAG only. However, the combination of these two was more effective in distinguishing normal individuals from OHT subjects or pre-POAG patients without VF defects, with better performance than the combination of peripapillary retinal nerve fiber layer (RNFL) thickness and VF indicators.

CONCLUSIONS

Peripapillary retinal vessel densities were generally lower in early POAG patients compared to normal individuals. The combination of peripapillary superficial retinal VAD by OCTA with white-on-white VF testing improved the ability to distinguish POAG patients at early stage without function impairment, which may help in providing reference and guidance for the following-up and treatment of suspected POAG patients.

Rate of Initial Optic Nerve Head Capillary Density Loss and Risk of Visual Field Progression

Importance

Rapid initial optic nerve head capillary density loss may be used to assess the risk of glaucoma visual field progression.

Objective

To investigate the association between the rate of initial optic nerve head capillary density loss from optical coherence tomography angiography (OCTA) and visual field progression.

Design, Setting, Participants

This was a retrospective study of a longitudinal cohort at a glaucoma referral center. A total of 167 eyes (96 with primary open-angle glaucoma and 71 with glaucoma suspect) of 109 patients were monitored for a mean (SD) of 5.7 (1.4) years from January 2015 to December 2022. Data analysis was undertaken in April 2023.

Main Outcomes and Measures

The rates of initial capillary density and average retinal nerve fiber layer loss were calculated from the first 3 optic nerve head OCTA and OCT scans, respectively, during the initial follow-up (mean [SD], 2.0 [1.0] years). Based on the median rate, eyes were categorized into fast and slow progressor groups. The association between initial capillary density change or retinal nerve fiber layer thinning and visual field progression was evaluated using linear-mixed and time-varying Cox models.

Results

A total of 167 eyes of 109 patients (mean [SD] age, 69.0 [11.1] years; 56 [51.4%] female and 53 [48.6%] male) were assessed. Eighty-three eyes were slow OCTA progressors, while 84 eyes were fast with mean capillary density loss of -0.45% per year and -1.17% per year, respectively (mean difference, -0.72%/year; 95% CI,-0.84 to -0.60; P < .001). Similarly, 83 eyes were slow OCT progressors, while 84 eyes were fast with mean retinal nerve fiber layer thinning of -0.09 μm per year and -0.60 μm per year, respectively (mean difference, -0.51 μm/year; 95% CI,-0.59 to -0.43; P < .001). The fast OCTA and OCT progressors were associated with more rapid visual field loss (mean difference, -0.18 dB/year; 95% CI,-0.30 to -0.06; P = .004 and -0.17 dB/year; 95% CI,-0.29 to -0.06; P = .002, respectively). Fast OCTA progressing eyes were more likely to have visual field progression (hazard ratio, 1.96; 95% CI, 1.04-3.69; P = .04). Seventeen of 52 eyes (32.7%; 95% CI, 32.5-32.8) with fast OCTA and OCT progression developed subsequent visual field likely progression.

Conclusion and Relevance

Rapid initial optic nerve head capillary density loss from OCTA was associated with a faster rate of visual field progression and a doubling of the risk of developing event progression in this study. These findings may support clinical use of OCTA and OCT optic nerve head measurements for risk assessment of glaucoma progression.

Smoking Intensity is Associated With Progressive Optic Nerve Head Vessel Density Loss in Glaucoma

PRCIS

A lifetime history of greater smoking consumption was associated with faster vessel density loss over time. Smoking intensity should be considered when assessing the risk of glaucoma progression, as well as its management.

PURPOSE

To investigate the relationship of smoking and smoking intensity, with the rate of optic nerve head (ONH) whole image capillary density (wiCD) loss in primary open angle glaucoma (POAG) and glaucoma suspect patients.

METHODS

In this longitudinal study, patients with POAG who had at least 2 years of follow-up and optical coherence tomography angiography (OCTA) performed at a minimum of 4 visits were selected for study. The smoking intensity was calculated as the pack-year at the baseline OCTA. Univariable and multivariable linear mixed models were used to determine the effect of each parameter on the rates of wiCD loss over time. Nonlinear least-squares estimation with piecewise regression model was used to investigate the cutoff point for the relationship between wiCD loss and smoking intensity.

RESULTS

One hundred sixty-four eyes (69 glaucoma suspect and 95 POAG) of 110 patients were included with a mean (95% CI) follow-up of 4.0 (3.9 to 4.1) years. Of the 110 patients, 50 (45.5%) had a reported history of smoking. Greater smoking intensity was associated with faster wiCD loss [-0.11 (-0.23 to 0.00)] %/year per 10 pack-year higher; P =0.048) after adjusting for covariates. The wiCD thinning became significantly faster when smoking intensity was greater than 22.2 pack-years. Smoking had no effect on the rate of wiCD thinning in patients who smoked <22.2 pack-years during their lifetime.

CONCLUSIONS

A history of greater smoking consumption was associated with faster vessel density loss, suggesting smoking intensity as a potential risk factor for glaucoma.

Unveiling Novel Structural Biomarkers for the Diagnosis of Glaucoma

Glaucoma, a leading cause of irreversible blindness, poses a significant global health burden. Early detection is crucial for effective management and prevention of vision loss. This study presents a collection of novel structural biomarkers in glaucoma diagnosis. By employing advanced imaging techniques and data analysis algorithms, we now can recognize indicators of glaucomatous progression. Many research studies have revealed a correlation between the structural changes in the eye or brain, particularly in the optic nerve head and retinal nerve fiber layer, and the progression of glaucoma. These biomarkers demonstrate value in distinguishing glaucomatous eyes from healthy ones, even in the early stages of the disease. By facilitating timely detection and monitoring, they hold the potential to mitigate vision impairment and improve patient outcomes. This study marks an advancement in the field of glaucoma, offering a promising avenue for enhancing the diagnosis and possible management.

OCTA on the density of optic nerve microvessels in myopic population with ocular hypertension

OBJECTIVE

To measure functional, structural, and blood flow parameters of the optic disk in myopic patients with ocular hypertension (OHT) and myopic patients using optical coherence tomography angiography (OCTA), this study aims to investigate the variability of each parameter between the two groups, and to analyze the correlation between the RNFL thickness and blood flow parameters, as well as the diagnostic value of these blood flow parameters for myopic patients with OHT.

METHODS

This was a cross-sectional study. Myopic adults who were attending the Eye Center of Jinan Second People's Hospital between December 2020 and January 2022, and who had a confirmed diagnosis of OHT, were enrolled. This cohort constituted the myopic group. In these subjects, retinal nerve fiber layer (RNFL) thickness and blood flow parameters within the superficial optic disk 6 × 6 mm area were measured using OCTA. The optic disk blood flow parameters included radial peripapillary capillaries (RPC) perfusion density (PD) in nasal, temporal, superior, and inferior sectors. Visual field assessments were conducted using a Humphrey visual field meter to obtain the visual field index (VFI) and pattern standard deviation (PSD). SPSS 22.0 statistical software was utilized to determine if statistical differences existed between the parameters of the two groups and to analyze the correlation between blood flow parameters and RNFL thickness. Additionally, the area under the subject's operating characteristic curve (AUROC) was used to assess the diagnostic value of blood flow parameters for myopic patients with OHT.

RESULTS

There was no statistical difference in PSD and VFI in the OHT group compared with the myopic group (P = 0.351, 0.242). The RNFL thickness was (103.64 ± 8.13) μm and (97.56 ± 12.94) μm in the myopic and OHT groups, respectively. There was no statistical difference in RNFL thickness between the OHT and myopic group (P = 0.052). The PD of radial peripapillary capillaries (RPC) in nasal, temporal, superior, and inferior sectors showed an overall decreasing trend between the myopic and OHT groups, but there was a statistical difference only in the temporal sector (P = 0.008). Correlation analysis of blood flow parameters and structural parameters showed that the PD in the temporal sector and RNFL thickness were not correlated (P = 0.263). By plotting the AUROC of blood flow parameter, it was found that OCTA had good value in diagnosing myopic patients with OHT, and the PD of the temporal sector had higher diagnostic value for differentiating the OHT group from myopic group (AUROC = 0.718, P = 0.008) CONCLUSIONS: Compared with the myopic group, blood flow parameters decreased in the OHT group, while structural and functional parameters did not change significantly, suggesting that blood flow damage may have occurred earlier in myopic patients with OHT, by the correlation analysis between structural and blood flow parameters. OCTA has good diagnostic value for myopic patients with OHT.

Intraretinal microvascular alterations in indirect traumatic optic neuropathy using optical coherence tomography angiography

PURPOSE

To quantitatively evaluate macular and peripapillary microvascular alterations in patients with indirect traumatic optic neuropathy (TON) compared to normal controls using optical coherence tomography angiography (OCT-A) and determine their associations with other ocular parameters.

METHODS

We enrolled 33 eyes of 33 patients with TON and 34 eyes of 34 healthy controls. OCT-A was used to generate microvascular structure images of the superficial retinal capillary plexus (SRCP), deep retinal capillary plexus (DRCP), and radial peripapillary capillary (RPC) segment in the macula and peripapillary area. Functional and structural parameters such as best-corrected visual acuity, visual field, peripapillary retinal nerve fibre layer (pRNFL) thickness, macular ganglion cell-inner plexiform layer (mGCIPL) thickness, OCT-A variables were compared between TON patients and controls. Age, gender, and spherical equivalent refractive errors were statistically adjusted for the analysis.

RESULTS

OCT-A revealed a significant reduction of the average vessel density in the RPC segment in TON patients compared to controls (48.5% ± 6.28 vs. 57.88% ± 3.06%, P < 0.0001, corrected P < 0.0001). When comparing sectors, the vessel density of the RPC segment in TON patients was also significantly lower in all four quadrants compared to healthy controls. The inferior sector vessel density of the RPC segment was significantly associated with visual field defects (P = 0.0253) and visual acuity (P = 0.0369). The temporal sector vessel density of DRCP was also associated with visual field defects (P = 0.0377). The RPC segment in the superior and inferior sector vessel density displayed a significant association with the corresponding regional pRNFL thickness (P = 0.0248 and <0.0001, respectively).

CONCLUSIONS

Patients with indirect TON exhibit significant microvascular alterations compared to controls. This study confirms that TON can induce intraretinal microvascular changes and suggests that OCT-A may serve as a useful biomarker for assessing visual functional and structural changes.

Papillary and peripapillary vascular densities and corresponding correlation with peripapillary retinal thicknesses using optical coherence tomography angiography in healthy children and adolescents

To evaluate the peripapillary retinal thickness (PPRT), vascular density (PPVD), and disc vascular density (PVD) and their correlations in normal healthy children using optical coherence tomography angiography (OCTA). This was a cross-sectional study of 70 eyes from 36 normal healthy children aged 6-18 years who performed optic nerve head scans using OCTA. The PPRT included the peripapillary nerve fiber layer (PP-RNFLT), inner retina (PP-IRT), middle retinal thickness, and outer retinal thicknesses. The PP-RNFLT and PP-IRT were not significantly different between males and females. Superior nasal peripapillary RNFLT and IRT were significantly affected by age (ANOVA, P > 0.05). The PP-IRT and PP-RNFLT were lower in the 7-11 years old group in comparison with the other 3 groups (Post hoc Tukey test, P value < 0.05). Age and sex-matched PVD were not correlated with PPVD (partial correlation, P > 0.05). PPRT was not correlated with PVD, PPVD, superficial and deep retinal vascular densities, and choroidal vascular density. This study demonstrated that PPRT appears to change during growth in childhood. Superior nasal PPRT was affected more in the groups, decreasing from less than 7 years old to 7-11 years old and then back to pre-reduction values after 11 years old.

Optical coherence tomography angiography in glaucoma

The use of optical coherence tomography angiography (OCTA) holds significant promise for optometrists in the diagnosis and management of glaucoma. It offers reliable differentiation of glaucomatous eyes from healthy ones and extends monitoring capabilities for advanced cases. OCTA represents a valuable addition to traditional assessment methods, particularly in complex cases. Glaucoma, a major cause of irreversible blindness, is traditionally diagnosed using structural and functional metrics. With growing interest, OCTA is being explored to diagnose, monitor, and manage glaucoma. This review focuses on the application of OCTA in glaucoma patients. A database search was carried out using Embase Elsevier (n = 664), PubMed (n = 574), and Cochrane Central Register of Controlled Trials (n = 19) on 15 August 2023. After deduplication and screening, 272 original papers were included in the narrative review. Inclusion criteria comprised English-language original studies on OCTA use in human glaucoma patients, with or without healthy controls. Exclusion criteria encompassed animal studies, in-vivo/in-vitro research, reviews, and congress abstracts. OCTA has good repeatability and reproducibility. OCTA metrics have good discriminatory power to differentiate glaucomatous eyes from healthy eyes and show strong associations with structural changes and visual field defects. OCTA can extend the monitoring of advanced glaucoma, addressing the 'floor effect' of traditional structural measurements. OCTA metrics can be affected by the choice of OCTA machine, post-image processing algorithms, systemic diseases, and ocular factors. Image artefacts can affect the accuracy of OCTA measurements, and proper scan quality evaluation is crucial to ensure reliable results. Additionally, artificial intelligence techniques offer promise for enhancing the diagnostic accuracy of OCTA by combining data from various retinal layers and regions. OCTA complements traditional methods in assessing glaucoma, especially in challenging cases, providing valuable insights for detection and management. Further research and clinical validation are needed to integrate OCTA into routine practice.

Racial Differences in the Diagnostic Accuracy of OCT Angiography Macular Vessel Density for Glaucoma

PURPOSE

To evaluate and compare the diagnostic accuracy of macular vessel density (VD) measured by OCT angiography (OCTA) in individuals of African descent (AD) and European descent (ED) with open-angle glaucoma.

DESIGN

Observational, cross sectional study.

PARTICIPANTS

A total of 176 eyes of 123 patients with glaucoma and 140 eyes of 88 healthy participants from the Diagnostic Innovations in Glaucoma Study.

METHODS

Whole-image ganglion cell complex (wiGCC) thickness and macular VD (parafoveal VD and perifoveal VD) were obtained from 6 × 6 macula scans. Area under the receiver operating characteristic (AUROC) curves were used to evaluate the diagnostic accuracy of macular VD and ganglion cell complex (GCC) thickness in AD and ED participants after adjusting for confounders such as age, visual field mean deviation (VF MD), signal strength index, axial length, self-reported hypertension and diabetes.

MAIN OUTCOME MEASURES

Macular VD and wiGCC measurements.

RESULTS

Parafoveal and perifoveal VD were significantly lower in ED than AD patients with glaucoma. Parafoveal and perifoveal VD performed significantly worse in AD participants compared with ED participants for detection of glaucoma (adjusted AUROC, 0.75 [95% confidence interval (CI), 0.62, 0.87], 0.85 [95% CI, 0.79, 0.90], P = 0.035; and 0.82 [95% CI, 0.70, 0.92], 0.91 [95% CI, 0.87, 0.94], respectively; P = 0.020). In contrast to VD, diagnostic accuracy of GCC thickness was similar in AD and ED individuals (adjusted AUROC, 0.89 [95% CI, 0.79, 0.96], 0.92 [95% CI, 0.86, 0.96], respectively; P = 0.313). The diagnostic accuracies of both macular VD and GCC thickness for differentiating between glaucoma and healthy eyes increased with increasing VF MD in both AD and ED participants.

CONCLUSIONS

Diagnostic performance of OCTA macular VD, but not GCC thickness, for glaucoma detection varies by race. Moreover, macular VD parameters had lower accuracy for detecting glaucoma in AD individuals than in ED individuals. The diagnostic performance of macular VD is race-dependent, and, therefore, race should be taken into consideration when interpreting macular OCTA results.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Cardiac Surgery Patients Have Reduced Vascularity and Structural Defects of the Retina Similar to Persons with Open-Angle Glaucoma

(1) Background: Growing evidence suggests impairment of ocular blood flow in open-angle glaucoma (OAG) pathology, but little is known about the effect of an impaired cardiovascular supply on the structural and vascular parameters of the retina. This study aims to investigate the variations of these parameters in OAG patients compared to patients undergoing cardiac surgery (CS) with cardiopulmonary bypass. (2) Methods: Prospective observational study with 82 subjects (30 controls, 33 OAG patients, and 19 CS patients) who underwent ophthalmological assessment by swept-source OCT and CDI in one randomly selected eye. (3) Results: In the CS group, OA and SPCA PSV and EDV were significantly lower, OA and SPCA RI were significantly higher compared to the OAG and healthy subjects (p = 0.000-0.013), and SPCA EDV correlated with linear CDR (r = -0.508, p = 0.027). Temporal ONH sectors of GCL++ and GCL+ layers in the CS group did not differ significantly compared to the OAG patients (p = 0.085 and p = 0.220). The CS patients had significantly thinner GCL++ and GCL+ layers in the inner sectors (p = 0.000-0.038) compared to healthy subjects, and these layers correlated with the CRA PSV, EDV, and RI and SPCA PSV (p = 0.005-0.047). (4) Conclusions: CS patients had lower vascular and structural parameters in the ONH, and macula compared to the healthy controls that were similar to persons with OAG.

From the past to the present, optical coherence tomography in glaucoma: a practical guide to a common disease

Glaucoma comprises a group of disorders of the optic nerve that cause degenerative optic neuropathy, characterised by failure of neuroretinal rim tissue in the optic nerve head, retinal nerve fibre layer, and retinal ganglion cells. Glaucoma imposes a serious epidemiological threat, with an steady increase in the global number of cases. In the current ophthalmological practice, glaucoma is diagnosed via a series of examinations, including routine funduscopic examination, ocular tonometry, gonioscopy, measurement of the visual field, and assessment using the optical coherence tomography (OCT) technique. Nowadays, the OCT technique helps in systematising the diagnostic pathway and is a basic diagnostic tool for detection of early glaucomatous eye changes. It is also vital in assessing progression and monitoring treatment results of patients. The aim of this review was to present the OCT technique as a main tool in diagnosing and monitoring glaucoma.

Peripapillary Perfusion Analysis Using Optical Coherence Tomography Angiography in Patients with Normal Tension Glaucoma

PURPOSE

This study aimed to assess the difference in the vascular parameters of perfusion in the optic nerve head in normal tension glaucoma (NTG) across disease stages using optical coherence tomography angiography and its correlation with peripapillary retinal nerve fiber layer (RNFL) thickness.

METHODS

In this retrospective study, 83 eyes with varying stages of NTG (25 mild, 31 moderate, and 27 severe) and 90 healthy eyes were enrolled. The perfusion density (PD) and flux index (FI) of the optic nerve head divided into four sectors were determined. We compared the vascular, structural, and functional parameters between normal and glaucomatous eyes and performed a subgroup analysis among the NTG stages. Pearson correlation coefficient was used to assess the topographic correlation between vascular parameters and RNFL thickness.

RESULTS

PD and FI were significantly decreased in the NTG group. Subgroup analysis revealed a significant decrease in vascular parameters in most regions in the NTG group, except for the nasal PD and temporal FI. Post hoc analysis showed a significant decrease in PD in the inferior region across all severity levels (mild vs. moderate, p = 0.012; moderate vs. severe, p = 0.012; mild vs. severe, p < 0.001). PD and FI were strongly correlated with RNFL thickness in all quadrants (all p < 0.001), with the strongest correlation observed in the inferior region.

CONCLUSIONS

Vascular parameters were significantly decreased in glaucomatous eyes, and the degree of decrease in vascular parameters was proportional to glaucoma severity. Peripapillary perfusion analysis using optical coherence tomography angiography may complement other measurements used for glaucoma diagnosis.

Longitudinal change of peripapillary vessel density and retinal nerve fibre layer thickness in normal tension and primary angle closure glaucoma

PURPOSE

To compare the rates of peripapillary vessel density (pVD) loss and retinal nerve fibre layer (RNFL) thinning in normal tension glaucoma (NTG) and primary angle closure glaucoma (PACG).

METHODS

Baseline age and severity-matched NTG and PACG eyes (75 eyes of 60 patients for each subtype) were observed longitudinally. All participants' RNFL thickness were measured by optical coherence tomography (OCT); pVD were measured by swept-source OCT-angiography (OCT-A) and quantified by a customised MATLAB program. The rate of pVD loss and RNFL thinning were estimated by linear mixed-effects models.

RESULTS

NTG eyes had significant pVD loss in all sectors (p≤0.05) while PACG eyes' pVD loss was borderline significant in the global region (p=0.05). Significant RNFL thinning was detected in the inferotemporal and superonasal regions of both groups, and the superotemporal region in the NTG group (all p≤0.02). NTG had faster rate of pVD loss in the global (difference (95% CI) -1.08 (-1.90 to -0.27) %/year), temporal (-1.57 (-2.91 to -0.23) %/year) and superotemporal (-1.46 (-2.65 to -0.26) %/year) regions than PACG (all p≤0.02), without significant difference of the rate of RNFL thinning. A lower baseline mean deviation (MD) was associated with a faster rate of global pVD loss, while a lower baseline pVD was associated with a slower rate of global pVD loss in multivariable analyses (both p≤0.04).

CONCLUSIONS

NTG had more extensive and faster rate of pVD loss than PACG. Baseline global pVD and MD were independently associated with the rate of pVD loss in NTG.

Diagnostic performance of wide-field optical coherence tomography angiography for high myopic glaucoma

Diagnosing and monitoring glaucoma in high myopic (HM) eyes are becoming very important; however, it is challenging to diagnose this condition. This study aimed to evaluate the diagnostic ability of wide-field optical coherence tomography angiography (WF-OCTA) maps for the detection of glaucomatous damage in eyes with HM and to compare the diagnostic ability of WF-OCTA maps with that of conventional imaging approaches, including swept-source optical coherence tomography (SS-OCT) wide-field maps. In this retrospective observational study, a total 62 HM-healthy eyes and 140 HM eyes with open-angle glaucoma were included. Patients underwent a comprehensive ocular examination, including SS-OCT wide-field and 12 × 12 WF-OCTA scans. The WF-OCTA map represents the peripapillary and macular superficial vascular density maps. Glaucoma specialists determined the presence of glaucomatous damage in HM eyes by reading the WF-OCTA map and comparing its sensitivity and specificity with those of conventional SS-OCT images. The sensitivity and specificity of 12 × 12 WF-OCTA scans for HM-glaucoma diagnosis were 87.28% and 86.94%, respectively, while, the sensitivity and specificity of SS-OCT wide-field maps for HM-glaucoma diagnosis were 87.49% and 80.51%, respectively. The specificity of the WF-OCTA map was significantly higher than that of the SS-OCT wide-field map (p < 0.05). The sensitivity of the WF-OCTA map was comparable with that of the SS-OCT wide-field map (p = 0.078). The WF-OCTA map showed good diagnostic ability for discriminating HM-glaucomatous eyes from HM-healthy eyes. As a complementary method to an alternative imaging modality, WF-OCTA mapping can be a useful tool for the detection of HM glaucoma.

Quantitative measurement of retinal nerve fiber layer thickness and its correlation with optical coherence tomography angiography vascular biomarker changes in preclinical diabetic retinopathy

PURPOSE

The present study was done to assess the use of optical coherence tomography angiography (OCTA) in detecting earlier stages of diabetic retinopathy and for the early management and effective blood glucose control in preclinical diabetic patients for preventing retinal nerve fiber layer (RNFL) thinning.

METHODS

A tertiary care center-based prospective observational study was conducted from the year 2021 to 2022 in the Department of Ophthalmology. The study included 50 cases and 50 controls. The parameters analyzed by using OCTA (Topcon 3D OCT-1 Maestro2) were RNFL thickness and peripapillary vessel density.

RESULTS

We found that the RNFL thickness in the temporal and superior disc in patients with preclinical diabetic retinopathy was significantly (0.041 and 0.044, respectively) decreased. The duration of diabetes and glycated hemoglobin (HbA1c) were the risk factors for peripapillary vessel density reduction in patients with preclinical diabetic retinopathy (P < 0.001).

CONCLUSION

RNFL thinning is an early sign of retinal neurodegeneration and is associated with peripapillary vessel density reduction. Early management and effective blood glucose control in diabetes patients may be beneficial for preventing RNFL thinning in superior and temporal disc.

Deep Learning Estimation of 10-2 Visual Field Map Based on Macular Optical Coherence Tomography Angiography Measurements

PURPOSE

To develop deep learning (DL) models estimating the central visual field (VF) from optical coherence tomography angiography (OCTA) vessel density (VD) measurements.

DESIGN

Development and validation of a deep learning model.

METHODS

A total of 1051 10-2 VF OCTA pairs from healthy, glaucoma suspects, and glaucoma eyes were included. DL models were trained on en face macula VD images from OCTA to estimate 10-2 mean deviation (MD), pattern standard deviation (PSD), 68 total deviation (TD) and pattern deviation (PD) values and compared with a linear regression (LR) model with the same input. Accuracy of the models was evaluated by calculating the average mean absolute error (MAE) and the R2 (squared Pearson correlation coefficients) of the estimated and actual VF values.

RESULTS

DL models predicting 10-2 MD achieved R2 of 0.85 (95% confidence interval [CI], 74-0.92) for 10-2 MD and MAEs of 1.76 dB (95% CI, 1.39-2.17 dB) for MD. This was significantly better than mean linear estimates for 10-2 MD. The DL model outperformed the LR model for the estimation of pointwise TD values with an average MAE of 2.48 dB (95% CI, 1.99-3.02) and R2 of 0.69 (95% CI, 0.57-0.76) over all test points. The DL model outperformed the LR model for the estimation of all sectors.

CONCLUSIONS

DL models enable the estimation of VF loss from OCTA images with high accuracy. Applying DL to the OCTA images may enhance clinical decision making. It also may improve individualized patient care and risk stratification of patients who are at risk for central VF damage.

Peripapillary vessel density in healthy people, primary open-angle glaucoma, and normal-tension glaucoma

OBJECTIVE

To compare peripapillary vessel density using optical coherence tomography angiography (OCT-A) in eyes of healthy people, primary open-angle glaucoma (POAG), and normal-tension glaucoma (NTG).

METHODS

Thirty patients with POAG, 27 patients with NTG, and 29 healthy individuals in the control group were assessed. Capillary vessels in peripapillary retinal nerve fiber layer (RNFL) represented by whole image RPC (radial peripapillary capillary) density in an AngioDisc scan 4.5 × 4.5 mm centered on the optic disc, and ONH morphological variables (disc area, rim area, cup to disc area ratio (CDR)), and average peripapillary RNFL thickness were measured.

RESULTS

Differences in mean RPC, RNFL, disc area, rim area, and CDR between the groups were statistically significant (P < 0.05). The difference in RNFL thickness and rim area was not significant between NTG and healthy groups, while RPC and CDR showed a statistically significant difference between all pairs. The vessel density in the POAG group was 8.25% and 11.7% lower compared to the NTG and healthy groups, respectively; while the mean difference was less (2.97%) for the NTG and healthy group. In the POAG group, 67.2% of the variation in RPC can be explained by a model containing CDR and RNFL thickness, and in normal eyes 38.8% of the changes using a model containing RNFL.

CONCLUSION

The peripapillary vessel density is reduced in both types of glaucoma. The vessel density in NTG was significantly lower than in the healthy eyes, despite the lack of significant difference in RNFL thickness and neuroretinal rim area between them.

Vessel Density Features of Optical Coherence Tomography Angiography for Classification of Glaucoma Using Machine Learning

PRCIS

Machine learning (ML) based on the optical coherence tomography angiography vessel density features with different thresholds using a support vector machine (SVM) model provides excellent performance for glaucoma detection.

BACKGROUND

To assess the classification performance of ML based on the 4 vessel density features of peripapillary optical coherence tomography angiography for glaucoma detection.

METHODS

Images from 119 eyes of 119 glaucoma patients and 76 eyes of 76 healthy individuals were included. Four vessel density features of optical coherence tomography angiography images were developed using a threshold-based segmentation method and were integrated into 3 models of machine learning classifiers. Images were divided into 70% training set and 30% test set. Classification performances of SVM, random forest, and Gaussian Naive Bayes models were evaluated with the area under the receiver operating characteristic curve (AUC) and accuracy.

RESULTS

Glaucoma eyes had lower vessel densities at different thresholds. For differentiating glaucoma eyes, the best results were achieved with 70% and 100% thresholds, in which SVM classifier discriminated glaucoma from healthy eyes with an AUC of 1 and accuracy of 1. After SVM, the random forest classifier with 100% thresholds showed an AUC of 0.993 and an accuracy of 0.994. Furthermore, the AUC of our ML performance (SVM) was 0.96 in a subgroup analysis of mild and moderate glaucoma eyes.

CONCLUSIONS

ML based on the combined peripapillary vessel density features of total vessels and capillaries in the whole image and ring image could provide excellent performance for glaucoma detection.

Neurovascular dysfunction in glaucoma

Retinal ganglion cells, the neurons that die in glaucoma, are endowed with a high metabolism requiring optimal provision of oxygen and nutrients to sustain their activity. The timely regulation of blood flow is, therefore, essential to supply firing neurons in active areas with the oxygen and glucose they need for energy. Many glaucoma patients suffer from vascular deficits including reduced blood flow, impaired autoregulation, neurovascular coupling dysfunction, and blood-retina/brain-barrier breakdown. These processes are tightly regulated by a community of cells known as the neurovascular unit comprising neurons, endothelial cells, pericytes, Müller cells, astrocytes, and microglia. In this review, the neurovascular unit takes center stage as we examine the ability of its members to regulate neurovascular interactions and how their function might be altered during glaucomatous stress. Pericytes receive special attention based on recent data demonstrating their key role in the regulation of neurovascular coupling in physiological and pathological conditions. Of particular interest is the discovery and characterization of tunneling nanotubes, thin actin-based conduits that connect distal pericytes, which play essential roles in the complex spatial and temporal distribution of blood within the retinal capillary network. We discuss cellular and molecular mechanisms of neurovascular interactions and their pathophysiological implications, while highlighting opportunities to develop strategies for vascular protection and regeneration to improve functional outcomes in glaucoma.

Evaluation of the Optic Nerve Head Using Optical Coherence Tomography Angiography in Systemic Sclerosis Patients

PURPOSE

To quantify microvascular vessel density in the optic disc using optical coherence tomography angiography (OCTA) in patients with systemic sclerosis (SS); to determine whether there is a difference in values between patients and controls; and to correlate the OCTA measurements with disease activity, damage risk, and drug usage.

METHODS

Patients aged 20 - 76 years who were followed up after a diagnosis of SS and age- and gender-matched controls. The patients underwent RTVue-XR AngioVue OCTA imaging in this cross-sectional observational study.

RESULTS

A total of 61 eyes of 61 consecutive SS patients and 60 eyes of 60 controls were investigated. There was no statistically significant difference between the patients and control groups regarding the average RNFL (retinal fiber layer) and radial peripapillary capillary (RPC) vessel density (VD) measurements (p = 0.35, p = 0.25, respectively). As the antinuclear antibody (ANA) titer increased, RNFLsuperior (p = 0.01, r = - 0.327), RPCwhole (p = 0.029, r = 0.279), RPCperipapillary (p = 0.037, r = - 0.267), RPCsuperior (p = 0.003, r = - 0.371), and RPCinferior (p = 0.02, r = 0.297) values decreased with statistical significance. The RPCinside values were lower in anti-Scl-70-positive patients compared to patients negative for anti-Scl-70 (topoisomerase I) (p = 0.021). The RNFLnasal (p = 0.03, r = - 0.278) value decreased as the years of disease increased. The RPCinside value was higher in patients using hydroxychloroquine and calcium channel blockers than those who did not use them (p = 0.021 and p = 0.027, respectively). The RPCwhole, RPCperipapillary, and RPCnasal values were higher, with statistical significance in corticosteroid users than in those patients who did not use corticosteroids (p = 0.043, 0.030, and 0.033, respectively).

CONCLUSION

There was no significant difference between the patients and control groups regarding the average RPC VD measurements. However, since this is the first study to analyze optic disc vessel density in SS patients, optic nerve blood flow changes in scleroderma with OCTA could be studied.

Optic Nerve Head, Peripapillary and Macular Microvascular Characteristics in Patients With Unilateral Pseudoexfoliation Glaucoma

PRCIS

In unilateral pseudoexfoliation glaucoma (PEXG), there may be decreased choroidal vascularity index (CVI), radial peripapillary capillary plexus' perfusion and flow. CVI may also be reduced in fellow eyes, suggesting that PEXG is bilateral disease.

PURPOSE

Evaluation of peripapillary and macular choroidal microvascularity and radial peripapillary capillary plexus in both eyes with unilateral PEXG and healthy eyes.

MATERIALS AND METHODS

Ninety-six eyes of 48 patients with unilateral PEXG [PEX (+): 48 eyes with PEXG; PEX (-): 48 eyes without PEX] and the right eyes of 45 age- and sex-matched healthy controls were included in the study. CVI was calculated on enhanced depth imaging optical coherence tomography scans. Radial peripapillary capillary vascular layer were evaluated by OCT-angiography.

RESULTS

Macular CVI (mCVI), temporal and nasal peripapillary CVI (pCVI) was significantly decreased in the PEX (+) compared with the PEX (-) and control group ( P <0.05 for all). Although there was a significant difference between PEX (-) and the control group in terms of mCVI and temporal pCVI, there was no significant difference between the 2 groups in terms of nasal pCVI ( P =0.008, P =0.036, and P =0.604, respectively). There was a significant difference in perfusion density (PD) and flux index (FI) between PEX (+) group, PEX (-) group and control group in all quadrants and average value ( P <0.05 for all). Although the PD and FI values in all quadrants and average values of the PEX (-) group were lower than the control group, this difference was not significant.

CONCLUSIONS

CVI in the macula and peripapillary region was significantly decreased in eyes with PEXG. Similarly, PD and FI were lower in eyes with PEXG. Low mCVI and temporal pCVI can also be seen in eyes without PEX.

Association of macular OCT and OCTA parameters with visual acuity in glaucoma

BACKGROUND/AIMS

To investigate the association of macular optical coherence tomography (OCT)/OCT angiography (OCTA) parameters with visual acuity (VA) in glaucoma.

METHODS

144 pseudophakic primary open-angle glaucoma eyes were included. Foveal (fVD), parafoveal (pf), perifoveal (perifVD) and whole-image vessel densities (wiVD) of superficial and deep layers, and their corresponding ganglion cell complex (GCC) thicknesses were obtained from OCTA 6×6 mm2 macula scans. Foveal avascular zone (FAZ) area, FAZ circumference and foveal density-300 (FD300) were measured. Correlation between OCT/OCTA parameters and Logarithm of the Minimum Angle of Resolution VA (logMAR VA) in early and moderate-advanced glaucoma was evaluated with age and Signal Strength Index-adjusted mixed models. Area under receiver operating characteristic (AUC) was used to evaluate discriminative power of OCT/OCTA for decreased VA (<20/25).

RESULTS

In early glaucoma (80 eyes), no parameter correlated with VA. In moderate-advanced glaucoma (64 eyes), greater FAZ area (β=0.228) and circumference (β=0.063) correlated with worse VA (p<0.05), but not FD300. fThinner sectoral and global GCC was associated with worse VA (β=0.002-0.003, p<0.05), except for inferior hemifield perifGCC and wiGCC. For VD, lower superior hemifield superficial perifVD and wiVD (β=0.007-0.008) and deep fVD (β=0.004) correlated with worse VA (p<0.05). OCT/OCTA parameters showed modest ability to discriminate decreased VA, with the superior hemifield performing better than the inferior hemifield. In early glaucoma, GCC and VD showed similar discrimination (AUC=0.67-0.77). In moderate-advanced glaucoma, fGCC and pfGCC yielded higher AUC (0.75-0.81) than VD (AUC=0.63-0.72).

CONCLUSIONS

Some macular OCT/OCTA parameters were associated with VA in moderate-advanced, but not early glaucoma. These structural parameters may help identify glaucoma patients with impaired vision and reduced quality of life.

TRIAL REGISTRATION NUMBER

NCT00221897.

Comparison between open-angle glaucoma and angle-closure glaucoma regarding the short-term optic disc vessel density changes after trabeculectomy

To compare the microvasculature of the optic disc in open-angle glaucoma (OAG) and angle-closure glaucoma (ACG) after trabeculectomy. This study included 34 patients divided into two groups based on the angle: (1) the OAG Group, which included 24 eyes from 24 patients, and (2) the ACG Group, which included ten eyes from 10 patients. All patients were subjected to comprehensive ophthalmic examinations. It included best-corrected visual acuity (BCVA), Goldmann applanation tonometry, gonioscopy, slit-lamp biomicroscopy, dilated fundus examination, and stereoscopic examination of the optic disc. The central corneal thickness was measured using a Nidek AL scan optical biometer. The visual field was evaluated by standard automated perimetry using Humphrey Field Analyzer (24-2 Swedish interactive threshold algorithm; Carl-Zeiss Meditec, Dublin, CA). Moreover, optical coherence tomography angiography (OCT-A) was performed utilizing the RTVue XR Avanti scanner (Optovue Inc., Fremont, CA, USA) preoperatively as well as 1 month after surgery. There was a statistically significant increase in optic disc vessel density (VD) in the whole image, radial peripapillary, inferior, superior, temporal, and nasal quadrant in OAG after surgery. Regarding the change in VD after surgery in ACG patients, there was a statistically significant increase in optic disc VD in the whole image, radial peripapillary, inferior, superior, temporal, and nasal quadrant in ACG after surgery.Regarding the percentage of VD change following trabeculectomy surgery, there were highly significant differences between the two groups for the whole image, radial peripapillary, inferior quadrant, and temporal quadrant VD. Statistically significant changes were also observed in the superior and nasal quadrants of VD. However, no significant change in VD was detected within the disc. In conclusion, the optic disc VD improved after the reduction of intraocular pressure (IOP) by surgery in both OAG and ACG. However, ACG demonstrated a significant improvement than the OAG.

Optical Coherence Tomography Angiography (OCTA) Differences in Vessel Perfusion Density and Flux Index of the Optic Nerve and Peri-Papillary Area in Healthy, Glaucoma Suspect and Glaucomatous Eyes

Purpose

To assess the ability of vascular perfusion parameters determined by optical coherence tomography angiography (OCTA) to detect and monitor glaucoma.

Methods

This prospective study included healthy, glaucoma suspect and glaucomatous eyes. All eyes underwent comprehensive glaucoma examination, including visual field tests and ocular imaging scans by OCTA. Parameters measured included retinal nerve fiber layer (RNFL) thickness, ganglion cell analysis (GCA), vascular perfusion density (VPD) and flux index (FI) of the optic nerve and peri-papillary area. Ocular parameters in healthy, glaucoma suspect, and glaucomatous eyes were compared by generalized estimating equations (GEE) with adjustments for age, with their relationships analyzed by Pearson's correlation coefficient. Rates of change per year were compared in glaucomatous eyes with and without glaucoma progression.

Results

This study enrolled 238 eyes, including 56 healthy, 79 glaucoma suspect, and 103 glaucomatous eyes. After adjustments for age, the average VPD (45.40 ± 0.19% vs 45.05 ± 0.22% vs 42.89 ± 0.32%, p < 0.001) and FI (0.4210 ± 0.0055 vs 0.4105 ± 0.0039 vs 0.3801 ± 0.0048, p < 0.001) in these three groups differed significantly. Average VPD in the glaucoma group was inversely associated with the severity of glaucoma, being 43.99 ± 0.32%, 42.63 ± 0.43% and 39.27 ± 0.48% in eyes with early, moderate and severe glaucoma, respectively (p < 0.001). Average VPD, as well as VPD in the superior and inferior quadrants correlated well with both OCT determined RNFL and visual field parameters. The decreases per year in both superior (-0.012 vs -0.001, p = 0.002) and inferior (-0.008 vs -0.003, p = 0.007) FI were significantly greater in glaucomatous eyes with than without glaucoma progression.

Conclusion

Both VPD and FI as measured by OCTA are promising ocular parameters that can distinguish between normal and glaucomatous eyes. VPD is sensitive in comparing eyes at different glaucoma stages, whereas FI can detect rates of glaucoma progression.

Trial Registration

Thai Clinical Trial Registry, TCTR20181031002.

Neurovascular segregation of the retinal nerve fiber layer in glaucoma

The imaging data of one eye from 154 healthy and 143 glaucoma participants were acquired to evaluate the contributions of the neuronal and vascular components within the retinal nerve fiber layer (RNFL) for detecting glaucoma and modeling visual field loss through the use of optical coherence tomography (OCT) and OCT angiography. The neuronal and vascular components within the circumpapillary RNFL were independently evaluated. In healthy eyes, the neuronal component showed a stronger association with age (r = -0.52, p < 0.001) compared to measured RNFL thickness (r = -0.46, p < 0.001). Using the neuronal component alone improved detection of glaucoma (AUC: 0.890 ± 0.020) compared to measured RNFL thickness (AUC: 0.877 ± 0.021; χ2 = 5.54, p = 0.019). Inclusion of the capillary components with the sectoral neuronal component resulted in a significant improvement in glaucoma detection (AUC: 0.927 ± 0.015; χ2 = 15.34, p < 0.001). After adjusting for potential confounders, AUC increased to 0.952 ± 0.011. Results from modeling visual field loss in glaucoma eyes suggest that visual field losses associated with neuronal thinning were moderated in eyes with a larger capillary component. These findings suggest that segregation of the neurovascular components could help improve understanding of disease pathophysiology and affect disease management in glaucoma.

Ocular posterior segment microstructural and microvascular morphological changes in protein supplement-consuming bodybuilders

BACKGROUND

To determine the effects of protein supplement (whey protein powder (PP)) on retinal, choroidal and optic nerve head (ONH) microstructure and microvascular morphology in healthy bodybuilders.

METHODS

This cross-sectional study included 23 male adults (consumers, 23 right eyes) who had been routinely consuming whey PP for bodybuilding purposes for ≥ 3 months, and 21 age- and gender-matched healthy volunteers (non-consumers, 21 right eyes) who also attended the gym but did not consume any nutritional supplements. Participants underwent standard ocular exams, enhanced depth imaging optical coherence tomography (EDI OCT), and optical coherence tomography angiography (OCTA) after ≥ 8 h of rest and fasting.

RESULTS

Whey PP was consumed for a median of 9.5 (6-12) months. Whey PP consumers had a median age of 22 (21-22) years, while non-consumers had 21 (20-22) years (p = 0.067). Whey PP consumers had greater microstructural thickness than non-consumers, with subfoveal choroidal thickness (301.40 ± 38.91 versus 278.12 ± 33.58 µm; p = 0.035) being significantly different but not central macular thickness (270.55 ± 24.60 versus 265.85 ± 12.44 µm; p = 0.402). Despite a non-significant difference in superficial and deep capillary plexus vascular densities (VDs), whey PP consumers had relatively lower VDs than non-consumers in all macular regions (p > 0.05). Despite this, whey PP consumers displayed greater ONH VDs, as well as higher global RNFL thickness (116.75 ± 10.41 versus 114.50 ± 11.70 µm) than non-consumers (p > 0.05).

CONCLUSION

Protein supplements, particularly whey PPs, appear to be associated with different changes in the retina and choroid, as well as ONH microstructural and microvascular morphology, implying that paying attention to these clinical aspects when performing ocular tests in bodybuilders who consume nutritional supplements could be critical.

Sector-Based Regression Strategies to Reduce Refractive Error-Associated Glaucoma Diagnostic Bias When Using OCT and OCT Angiography

Purpose

This cross-sectional study aimed to investigate the sectoral variance of optical coherence tomography (OCT) and OCT angiography (OCTA) glaucoma diagnostic parameters across eyes with varying degrees of refractive error.

Methods

Healthy participants, including individuals with axial ametropia, enrolled in the Hong Kong FAMILY cohort were imaged using the Avanti/AngioVue OCT/OCTA system. The OCT and OCTA parameters obtained include peripapillary nerve fiber layer thickness (NFLT), peripapillary nerve fiber layer plexus capillary density (NFLP-CD), and macular ganglion cell complex thickness (GCCT). Sectoral measurements of NFLT, NFLP-CD, and GCCT were based on sectors and hemispheres.

Results

A total of 1339 eyes from 791 participants were stratified based on spherical equivalent refraction: high myopia (<-6 D), low myopia (-6 D to -1 D), emmetropia (-1 D to 1 D), and hyperopia (>1 D). Multivariable broken stick regression models, accounting for age, sex, and signal strength, showed that all NFLT sectors except temporally, the inferior GCCT hemisphere, and half of the NFLP-CD sectors were more affected by ametropia-related covariates than the corresponding global parameters. As expected, the false-positive rates in those sectors were elevated. Finally, sector-specific axial length (AL) and spherical equivalent (SE) adjustments helped reduce the elevated false-positive rates.

Conclusions

The effect of optical magnification is even more prominent among sectors than the global parameters. AL- and SE-based adjustments should be individualized to each sector to mitigate this magnification bias effectively.

Translational Relevance

Identifying sectoral differences among diagnostic parameters and adopting these sector-based adjustments into commercial OCT systems will hopefully reduce false-positive rates related to refractive error.

Association between HSP-Specific T-Cell Counts and Retinal Nerve Fiber Layer Thickness in Patients with Primary Open-Angle Glaucoma

Objective

Previous laboratory reports implicate heat shock protein (HSP)-specific T-cell responses in glaucoma pathogenesis; here, we aimed to provide direct clinical evidence by correlating systemic HSP-specific T-cell levels with glaucoma severity in patients with primary open-angle glaucoma (POAG).

Design

Cross-sectional case-control study.

Subjects

Thirty-two adult patients with POAG and 38 controls underwent blood draw and optic nerve imaging.

Methods

Peripheral blood monocytes (PBMC) were stimulated in culture with HSP27, α-crystallin, a member of the small HSP family, or HSP60. Both interferon-γ (IFN-γ)+ CD4+ T helper type 1 cells (Th1) and transforming growth factor-β1 (TGF-β1)+ CD4+ regulatory T cells (Treg) were quantified by flow cytometry and presented as a percentage of total PBMC counts. Relevant cytokines were measured using enzyme-linked immunosorbent assays. Retinal nerve fiber layer thickness (RNFLT) was measured with OCT. Pearson's correlation (r) was used to assess correlations.

Main Outcome Measures

Correlations of HSP-specific T-cell counts, and serum levels of corresponding cytokine levels with RNFLT.

Results

Patients with POAG (visual field mean deviation, -4.7 ± 4.0 dB) and controls were similar in age, gender, and body mass index. Moreover, 46.9% of POAG and 60.0% of control subjects had prior cataract surgery (P = 0.48). Although no significant difference in total nonstimulated CD4+ Th1 or Treg cells was detected, patients with POAG exhibited significantly higher frequencies of Th1 cells specific for HSP27, α-crystallin, or HSP60 than controls (7.3 ± 7.9% vs. 2.6 ± 2.0%, P = 0.004; 5.8 ± 2.7% vs. 1.8 ± 1.3%, P < 0.001; 13.2 ± 13.3 vs. 4.3 ± 5.2, P = 0.01; respectively), but similar Treg specific for the same HSPs compared with controls (P ≥ 0.10 for all). Concordantly, the serum levels of IFN-γ were higher in POAG than in controls (36.2 ± 12.1 pg/ml vs. 10.0 ± 4.3 pg/ml; P < 0.001), but TGF-β1 levels did not differ. Average RNFLT of both eyes negatively correlated with HSP27- and α-crystallin-specific Th1 cell counts, and IFN-γ levels in all subjects after adjusting for age (partial correlation coefficient r = -0.31, P = 0.03; r = -0.52, p = 0.002; r = -0.72, P < 0.001, respectively).

Conclusions

Higher levels of HSP-specific Th1 cells are associated with thinner RNFLT in patients with POAG and control subjects. The significant inverse relationship between systemic HSP-specific Th1 cell count and RNFLT supports the role of these T cells in glaucomatous neurodegeneration.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Evaluation of microvascular changes in the retina and choriocapillaris in primary glaucoma and neuromyelitis optica spectrum disorder with optical coherence tomography angiography

BACKGROUND

To assess quantitatively the microvascular changes in the retina and choroid of healthy eyes, eyes of subjects with primary angle-closure glaucoma (PACG), primary open-angle glaucoma (POAG) and neuromyelitis optica spectrum disorder (NMOSD) using optical coherence tomography angiography (OCTA).

METHODS

A series of healthy individuals and subjects with PACG, POAG and NMOSD were recruited in this cross-sectional study. OCTA was performed to capture the optic nerve head and macula images and the vessel density (VD) and retinal nerve fiber layer (RNFL) thickness were quantified. The choriocapillary flow density (CFD) was calculated as the percentage of flow area to the whole selected area.

RESULTS

A total of 68 PACG subjects, 25 POAG subjects, 51 NMOSD subjects and 37 healthy controls were enrolled. Significant decreases in peripapillary VD and RNFL thickness were observed in PACG (p < 0.001) and POAG (p < 0.001) eyes and also in NMOSD subjects with an optic neuritis history (p < 0.001) compared with healthy controls. Unaffected eyes in PACG and POAG subjects had lower baseline peripapillary VD than healthy controls (p = 0.002 and p = 0.011, respectively). PACG eyes showed a lower baseline CFD than POAG (p = 0.0027) and the CFD in early and advanced PACG eyes showed a significantly much more decrease than POAG (p = 0.002 and p < 0.001, respectively).

CONCLUSIONS

The peripapillary vessel density and RNFL thickness was reduced in glaucomatous and NMOSD eyes compared with healthy controls. PACG eyes showed a lower CFD than POAG and the distinct peripapillary and choriocapillaris microvasculature changes may be correlated to different PACG and POAG pathogenesis.

Optical coherence tomography angiography characteristics of retinochoroidal and optic nerve head microcirculation in cryptogenic organizing pneumonia

BACKGROUND

To assess retinochoroidal and optic nerve head microcirculation alterations in cryptogenic organizing pneumonia.

METHODS

Thirty cryptogenic organizing pneumonia patients in the resolution phase (group 1, 30 right eyes) and 33 healthy subjects (group 2, 33 right eyes) were compared. Patients had 40 mg/day corticosteroids for 8-10 days, and a pulmonary function test, which revealed only minimally restrictive ventilation features. After gathering demographic data, a comprehensive ophthalmological exam and optical coherence tomography angiography were performed three months following maximum disease resolution with corticosteroid therapy RESULTS: Groups 1 and 2 had mean ages of 54.37±14.87 and 49.61±12.36 years, respectively (P = 0.171). Despite the lack of statistical significance, superficial and deep capillary plexus vessel densities in all macular regions were lower in group 1, as were foveal avascular zone parameters (P>0.05). However, the outer retinal and choriocapillaris flows increased significantly in group 1, especially in select areas (P<0.001, for both). There were no significant differences in whole image (P = 0.346), inside disk (P = 0.438), or peripapillary (P = 0.185) optic nerve head vessel densities between the two groups; however, nasal (P<0.001) and inferior quadrant (P = 0.006) vessel densities differed significantly. Global retinal nerve fiber layer thickness did not differ significantly between groups 1 and 2 (112.83±14.71 versus 111.45±12.74 µm, respectively; P = 0.692). Group 1, however, had significantly higher superior, nasal, and inferior quadrant, and significantly lower temporal quadrant retinal nerve fiber layer thickness (P<0.001, for all).

CONCLUSIONS

Concerning the impact of probable cryptogenic organizing pneumonia-induced hypoxia on ocular tissues, optical coherence tomography angiography assessments of retinochoroidal and optic nerve head microcirculation could be employed as a biomarker for cerebral microcirculation.

Visual Dysfunction in Parkinson's Disease

Non-motor symptoms in Parkinson's disease (PD) include ocular, visuoperceptive, and visuospatial impairments, which can occur as a result of the underlying neurodegenerative process. Ocular impairments can affect various aspects of vision and eye movement. Thus, patients can show dry eyes, blepharospasm, reduced blink rate, saccadic eye movement abnormalities, smooth pursuit deficits, and impaired voluntary and reflexive eye movements. Furthermore, visuoperceptive impairments affect the ability to perceive and recognize visual stimuli accurately, including impaired contrast sensitivity and reduced visual acuity, color discrimination, and object recognition. Visuospatial impairments are also remarkable, including difficulties perceiving and interpreting spatial relationships between objects and difficulties judging distances or navigating through the environment. Moreover, PD patients can present visuospatial attention problems, with difficulties attending to visual stimuli in a spatially organized manner. Moreover, PD patients also show perceptual disturbances affecting their ability to interpret and determine meaning from visual stimuli. And, for instance, visual hallucinations are common in PD patients. Nevertheless, the neurobiological bases of visual-related disorders in PD are complex and not fully understood. This review intends to provide a comprehensive description of visual disturbances in PD, from sensory to perceptual alterations, addressing their neuroanatomical, functional, and neurochemical correlates. Structural changes, particularly in posterior cortical regions, are described, as well as functional alterations, both in cortical and subcortical regions, which are shown in relation to specific neuropsychological results. Similarly, although the involvement of different neurotransmitter systems is controversial, data about neurochemical alterations related to visual impairments are presented, especially dopaminergic, cholinergic, and serotoninergic systems.

Change of Choroidal Microvasculature Dropout After Trabeculectomy as Assessed by Optical Coherence Tomography Angiography

PRCIS

Reduction in the angular circumference of choroidal microvascular dropout (CMvD AC) was found in POAG patients after trabeculectomy. Greater percentage of IOP reduction was significantly associated with decreased CMvD AC.

PURPOSE

The purpose of this study was to investigate the change of choroidal microvasculature dropout (CMvD) after trabeculectomy and its associated factors in primary open angle glaucoma (POAG) eyes using optical coherence tomography angiography.

METHODS

Fifty eyes of 50 POAG participants who had preoperative CMvD and underwent trabeculectomy were prospectively enrolled. Angular circumference (AC) of CMvD was determined from choroidal layer images by optical coherence tomography angiography preoperatively and at postoperative 1 year. The cutoff for significant AC of CMvD decrease was determined by the Bland-Altman method, and accordingly, patients were divided into 2, decreased and stable/increased CMvD AC groups. Changes in intraocular pressure (IOP) and CMvD AC were compared between the groups preoperatively and at postoperative 1 year. Factors associated with CMvD AC decrease were assessed by linear regression analysis.

RESULTS

The cutoff for significant CMvD AC decrease was 3.58 degrees; accordingly, 26 eyes (52.0%) were categorized as decreased CMvD AC group. No significant intergroup differences in baseline characteristics were found. However, the decreased CMvD AC group presented significantly lower IOP (10.7±3.7 vs. 12.9±2.6 mm Hg, P =0.022), lower CMvD AC (32.03±33.95% vs. 53.44±39.33%, P =0.044), and higher parapapillary choroidal vessel density ( P =0.014) compared with the increased/stable CMvD AC group at postoperative 1 year. The greater percentage of IOP reduction was significantly associated with decreased CMvD AC ( P =0.046).

CONCLUSIONS

CMvD AC reduction associated with IOP lowering was found after trabeculectomy. The long-term clinical relevance of postoperative CMvD reduction should be further investigated.

Disagreement of Radial Peripapillary Capillary Density Among Four Optical Coherence Tomography Angiography Devices

Purpose

This prospective study evaluated the agreement among four optical coherence tomography angiography (OCTA) devices in the assessment of radial peripapillary capillary (RPC) density.

Methods

The study included 48 eyes of 48 subjects (14 healthy, 19 glaucomatous, and 15 non-glaucomatous optic neuropathy). Each participant was scanned using four OCTA devices in a random sequence: RTVue XR Avanti (RTVue), DRI OCT Triton (Triton), Revo NX 130 (Revo), and PLEX Elite 9000 (PlexE). All 6 × 6-mm grayscale OCTA images from each device were analyzed for RPC density using a customized algorithm. Agreement between each pair of devices was assessed using intraclass correlation coefficients (ICCs) and Bland-Altman plots.

Results

There was a poor correlation between devices in all comparisons (RTVue-Triton, ICC = 0.34; RTVue-Revo, ICC = 0.31; RTVue-PlexE, ICC = 0.28; Triton-Revo, ICC = 0.31; Triton-PlexE, ICC = 0.17; Revo-PlexE, ICC = 0.34). Significant proportional biases (P < 0.05) and wide limits of agreement with apparent constant biases were identified in all comparisons. The mean difference was greatest for the RTVue-Revo pair (-49.3%; 95% confidence interval [CI], -52.9 to -45.8) and smallest for the Triton-PlexE pair (-7.7%; 95% CI, -10.1 to -5.3).

Conclusions

The RPC densities obtained from each device had poor inter-device agreement and significant biases and cannot be used interchangeably.

Translational Relevance

RPC density obtained from different OCTA devices is not interchangeable; thus, the progression of optic neuropathy should be monitored using the same OCTA device.

Quantification of vascular morphology in optical coherence tomography angiography in primary open angle glaucoma

Purpose

To quantitatively measure and compare the vascular morphology in healthy eyes and eyes with primary open-angle glaucoma (POAG) using optical coherence tomography angiography (OCTA) scans.

Methods

This is a retrospective and cross-sectional study which include healthy individuals and individuals with POAG that underwent OCTA imaging at an academic center's glaucoma clinic. We analyzed OCTA scans of the macula and optic nerve head (ONH) of one eye from each subject to quantitatively measure vessel density (VD), vessel length density (VLD), and branchpoint density (BPD). We compared these 3 parameters between the healthy and POAG groups and used logistic regression classification models to determine their diagnostic value in differentiating healthy and glaucomatous eyes.

Results

We included 49 healthy subjects and 49 subjects with POAG. After age-adjusted analysis, the parameters of VD, VLD, and BPD were significantly reduced in eyes with POAG (P ​< ​0.001) in all scan layers and most significantly around the ONH. The parameter with the best performances were radial peripapillary capillary (RPC) VD [AUC (areas under the curve): 0.939 (0.891, 0.987)] which had statistically higher performances (P ​< ​0.05) than parameters in the superficial or deep layers. All 3 parameters in the RPC layer had statistically similar performances.

Conclusions

We found that VD, VLD, and BPD were reduced in glaucomatous eyes. The morphologic parameters of VLD and BPD had similar performances to the traditional parameter of VD in RPC layers. Our results suggest that vascular morphology parameters may provide additional value in the diagnosis and evaluation of glaucoma.

Optical Coherence Tomography and Optical Coherence Tomography Angiography: Essential Tools for Detecting Glaucoma and Disease Progression

Early diagnosis and detection of disease progression are critical to successful therapeutic intervention in glaucoma, the leading cause of irreversible blindness worldwide. Optical coherence tomography (OCT) is a non-invasive imaging technique that allows objective quantification in vivo of key glaucomatous structural changes in the retina and the optic nerve head (ONH). Advances in OCT technology have increased the scan speed and enhanced image quality, contributing to early glaucoma diagnosis and monitoring, as well as the visualization of critically important structures deep within the ONH, such as the lamina cribrosa. OCT angiography (OCTA) is a dye-free technique for noninvasively assessing ocular microvasculature, including capillaries within each plexus serving the macula, peripapillary retina and ONH regions, as well as the deeper vessels of the choroid. This layer-specific assessment of the microvasculature has provided evidence that retinal and choroidal vascular impairments can occur during early stages of glaucoma, suggesting that OCTA-derived measurements could be used as biomarkers for enhancing detection of glaucoma and its progression, as well as to reveal novel insights about pathophysiology. Moreover, these innovations have demonstrated that damage to the macula, a critical region for the vision-related quality of life, can be observed in the early stages of glaucomatous eyes, leading to a paradigm shift in glaucoma monitoring. Other advances in software and hardware, such as artificial intelligence-based algorithms, adaptive optics, and visible-light OCT, may further benefit clinical management of glaucoma in the future. This article reviews the utility of OCT and OCTA for glaucoma diagnosis and disease progression detection, emphasizes the importance of detecting macula damage in glaucoma, and highlights the future perspective of OCT and OCTA. We conclude that the OCT and OCTA are essential glaucoma detection and monitoring tools, leading to clinical and economic benefits for patients and society.

Usability of Real-Time Elastography for the Diagnosis of Primary Open Angle and Pseudoexfoliation Glaucoma

OBJECTIVES

This study aims to investigate real-time elastography (RTE) use in the evaluation of the optic nerve head (ONH) and peripapillary structures for the diagnosis of primary open angle (POAG) and pseudoexfoliation (PEX) glaucoma.

METHODS

This case-controlled study included 30 patients with POAG, 30 patients with PEX glaucoma, and 30 age-matched control subjects. All of the participants underwent comprehensive ophthalmological examinations covering vessel density of optic nerve and retinal nerve fiber layer (RNFL) thickness measurements with optical cohorence tomography angiography and mean deviation (MD) measurements with Humphrey II Perimetry Visual Field Analyzer. In vivo evaluation of the biomechanical properties of the ONH and peripapillary structures were performed with RTE in all participants.

RESULTS

We observed higher ratios of orbital fat to optic nerve head (ROFON) values (P = .008) and strain ratios of orbital fat to scleral-choroidal-retinal complex (ROFSCR) values (P = .004) in the POAG group compared with PEX glaucoma group and higher ROFON (P = .012) and ROFSCR values (P = .004) in PEX glaucoma group than the control group. ROFON and ROFSCR values were positively correlated with glaucoma duration and negatively correlated with MD, radial peripapillary vessel density (RPCVD), and inside disc vessel density in both glaucoma groups (P < .005; only in the PEX glaucoma group for MD and ROFSCR, P = .445).

CONCLUSION

Determining the biomechanical properties of ONH and peripapillary structures with RTE in glaucomatous eyes may offer a new perspective on the diagnosis and follow-up of the progression of the disease.

Detection of Relative Afferent Pupillary Defect and Its Correlation with Structural and Functional Asymmetry in Patients with Glaucoma Using Hitomiru, a Novel Hand-Held Pupillometer

Patients with asymmetric glaucomatous optic neuropathy (GON) present a relative afferent pupillary defect (RAPD) in the eye with more advanced damage. Although useful, pupillometric RAPD quantification is not widely used as it is not portable. Whether asymmetry of the peripapillary capillary perfusion density (CPD) detected using optical coherence tomography angiography correlates with the severity of RAPD remains unknown. This study assessed RAPD in 81 patients with GON using Hitomiru, a novel hand-held infrared binocular pupillometer. The correlation and ability to detect clinical RAPD based on the swinging flash light test of two independent RAPD parameters (the maximum pupil constriction ratio and the constriction maintenance capacity ratio) were assessed. The coefficient of determination (R²) was calculated between each of the two RAPD parameters and asymmetry of the circumpapillary retinal nerve fiber layer thickness (cpRNFLT), ganglion cell layer/inner plexiform layer thickness (GCL/IPLT), and CPD. The two RAPD parameters showed a correlation coefficient of 0.86 and areas under the receiver operating characteristic (ROC) curve of 0.85-0.88, with R² being 0.63-0.67 for the visual field, 0.35-0.45 for cpRNFLT, 0.45-0.49 for GCL/IPLT, and 0.53-0.59 for CPD asymmetry. Hitomiru has high discriminatory performance in detecting RAPD in patients with asymmetric GON. CPD asymmetry may better correlate with RAPD than cpRNFLT and GCL/IPLT asymmetry.

A comparison of peripapillary vessel density between subjects with normal-tension glaucoma and primary open-angle glaucoma with similar extents of glaucomatous damage

The purpose of this study was to identify differences in retinal microvasculature impairments between patients with normal-tension glaucoma (NTG) and those with primary open-angle glaucoma (POAG) with similar extents of structural and visual field damage. Participants with glaucoma-suspect (GS), NTG, POAG, and normal controls were consecutively enrolled. Peripapillary vessel density (VD) and perfusion density (PD) were compared among the groups. Linear regression analyses were performed to identify the relationship between VD, PD and visual field parameters. The VDs of the full areas were 18.3 ± 0.7, 17.3 ± 1.7, 16.5 ± 1.7, and 15.8 ± 2.3 mm^-1 in the control, GS, NTG, and POAG groups, respectively (P < 0.001). The VDs of the outer and inner areas and the PDs of all areas also differed significantly among the groups (all P < 0.001). In the NTG group, the VDs of the full, outer, and inner areas were significantly associated with all visual field parameters including the mean deviation (MD), pattern standard deviation (PSD), and visual field index (VFI). In the POAG group, the VDs of the full and inner areas were significantly associated with PSD and VFI but not with MD. In conclusion, with similar degrees of retinal nerve fiber layer thinning and visual field damage in both groups, the POAG group showed a lower peripapillary VD and PD than the NTG group. VD and PD were significantly associated with visual field loss.

Intrasession Repeatability of OCT Angiography Parameters in Neurodegenerative Disease

Purpose

To assess the intrasession repeatability of macular OCT angiography (OCTA) parameters in Alzheimer's disease (AD), mild cognitive impairment (MCI), Parkinson's disease (PD), and normal cognition (NC).

Design

Cross sectional study.

Subjects

Patients with a clinical diagnosis of AD, PD, MCI, or NC were imaged. Images with poor quality and of those with diabetes mellitus, glaucoma, or vitreoretinal disease were excluded from analysis.

Methods Intervention or Testing

All participants were imaged using the Zeiss Cirrus HD-5000 with AngioPlex (Carl Zeiss Meditec, Software Version 11.0.0.29946) and repeat OCTA images were obtained for both eyes. Perfusion density (PFD), vessel density (VD), and Foveal avascular zone (FAZ) area were measured from 3 × 3 mm and 6 × 6 mm OCTA images centered on the fovea using an ETDRS grid overlay.

Main Outcome Measures

Intraclass correlation coefficients were used to quantify repeatability of PFD, VD, and FAZ area measurements obtained from imaging.

Results

3 × 3 mm scans of 22 AD, 40 MCI, 21 PD, and 26 NC participants and 6 × 6 mm scans of 29 AD, 44 MCI, 29 PD, and 30 NC participants were analyzed. Repeatability values ranged from 0.64 (0.49-0.82) for 6 × 6 mm PFD in AD participants to 0.87 (0.67-0.92) for 3 × 3 mm PFD in AD participants. No significant differences were observed in repeatability between NC participants and those with neurodegenerative disease.

Conclusions

Overall, similar OCTA repeatability was observed between NC participants and those with neurodegeneration. Regardless of diagnostic group, macular OCTA metrics demonstrated moderate to good repeatability.

Financial Disclosures

The authors have no proprietary or commercial interest in any materials discussed in this article.

Longitudinal Changes in Peripapillary and Macular Vessel Densities in Glaucomatous Eyes With a Single-Hemifield Retinal Nerve Fiber Layer Defect

PRCIS

The peripapillary vessel density decreased significantly in the affected hemiretina compared with that in the intact hemiretina in glaucomatous eyes with a single-hemifield retinal nerve fiber layer defect.

PURPOSE

To evaluate the difference in the change rates of peripapillary vessel density (pVD) and macular vessel density (mVD) measured using optical coherence tomography angiography (OCTA) in glaucomatous eyes with a single-hemifield retinal nerve fiber layer (RNFL) defect.

MATERIALS AND METHODS

We performed a retrospective, longitudinal study of 25 patients with glaucoma who were followed up for at least 3 years, with a minimum of 4 visits after baseline OCTA. At each visit, all participants underwent OCTA examination, and the pVD, mVD were measured by removing the large vessels. Changes in the pVD, mVD, peripapillary RNFL thickness (pRNFLT), and macular ganglion cell inner plexiform layer thickness were investigated in the affected and intact hemispheres, and the differences between the 2 hemispheres were compared.

RESULTS

In the affected hemiretina, the pVD, mVD, pRNFLT, and mCGIPLT were reduced than that in the intact hemiretina (all, P < 0.001). The changes in pVD and mVD were statistically significant at the 2-year and 3-year follow-ups in the affected hemifield (all, P <0.05). However, pVD and mVD did not show statistically significant changes in the intact hemiretina throughout the follow-up visits. Although the pRNFLT decreased significantly at the 3-year follow-up, the macular ganglion cell inner plexiform layer thickness showed no statistical change at any follow-up visit. Compared with the intact hemisphere, pVD was the only parameter that showed significant changes throughout the follow-up period.

CONCLUSION

Although pVD and mVD decreased in the affected hemiretina, the reduction in pVD was significant compared with that in the intact hemiretina.

Combined Model of OCT Angiography and Structural OCT Parameters to Predict Paracentral Visual Field Loss in Primary Open-Angle Glaucoma

PURPOSE

To assess a model combining OCT angiography (OCTA) and OCT parameters to predict the severity of paracentral visual field (VF) loss in primary open-angle glaucoma (POAG).

DESIGN

Cross-sectional study.

PARTICIPANTS

Forty-four patients with POAG and 42 control subjects underwent OCTA and OCT imaging with a swept-source OCT device.

METHODS

The circumpapillary microvasculature was quantified for vessel density (cpVD) and flow (cpFlow) after delineation of Bruch's membrane opening and removal of large vessels. Retinal nerve fiber layer thickness (RNFLT) and Bruch's membrane opening-minimum rim width (BMO-MRW) were measured from structural OCT. Paracentral total deviation (PaTD) was defined as the average of the total deviation values within the central 10 degrees on Humphrey VF testing (24-2) for upper and lower hemifields. The OCT and OCTA parameters were measured in the affected hemisphere corresponding to the hemifield with lower PaTD for POAG patients. Models were created to predict affected PaTD based on RNFLT alone; RNFLT and BMO-MRW; OCTA alone; or RNFLT, BMO-MRW and OCTA parameters. The models were compared using coefficient of determination (r2) and Bayesian information criterion (BIC) score. Bayesian information criterion decrease of ≥6 indicates strong evidence for model improvement.

MAIN OUTCOME MEASURES

Performance of models containing OCT and OCTA parameters in predicting PaTD.

RESULTS

Patients with POAG and controls were similar in age and sex (65.9 ± 9.5 years and 38.4% male overall, P ≥ 0.56 for both). Average RNFLT, minimum RNFLT, average BMO-MRW, minimum BMO-MRW, cpVD, and cpFlow were all significantly lower (all P < 0.001) in the affected hemisphere in patients with POAG than in controls. In patients with POAG, the average mean deviation was -4.33 ± 3.25 dB; the PaTD of the affected hemifield averaged -4.55 ± 5.26 dB and correlated significantly with both OCTA and structural OCT parameters (r ≥ 0.43, P ≤ 0.004 for all). The model containing RNFLT, BMO-MRW, and OCTA parameters was superior in predicting affected PaTD (r2 = 0.47, BIC = 290.7), with higher r2 and lower BIC compared with all 3 other models.

CONCLUSIONS

A combined model of OCTA and structural OCT parameters can predict the severity of paracentral VF loss of the affected hemifield, supporting clinical utility of OCTA in patients with POAG with paracentral VF loss.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Microvascular and neural alterations in carotid cavernous fistulas: An optical coherence tomography angiography study

BACKGROUND

Current modalities for diagnosing carotid cavernous fistula (CCF) are inaccurate in analysing retinal microcirculations and nerve fibre changes. Retinal microvascular and neural alterations occur in CCF patients and can be quantitatively measured using optical coherence tomography angiography (OCTA). We measured the neurovascular changes in the eyes of CCF patients and used OCTA as a supplementary method.

METHODS

This cross-sectional study studied 54 eyes of 27 unilateral CCF subjects and 54 eyes of 27 healthy age- and sex-matched controls. OCTA parameters in the macula and optic nerve head (ONH) were analysed using a one-way analysis of variance with further Bonferroni corrections. Parameters with statistical significance were included in a multivariable binary logistic regression analysis and receiver operating characteristic (ROC) curves were generated.

RESULTS

There was significantly less deep-vessel density (DVD) and ONH-associated capillary density in both eyes of CCF patients than in controls, while the differences between the affected and contralateral eyes were insignificant. The retinal nerve fibre layer and ganglion cell complex thickness were lower in the affected eyes than in the contralateral or controlled eyes. ROC curves identified DVD and ONH-associated capillary density as significant parameters in both eyes of CCF patients.

CONCLUSION

The retinal microvascular circulation was affected in both eyes of unilateral CCF patients. Microvascular alterations occurred before retinal neural damage. This quantitative study suggests a supplementary measurement for diagnosing CCF and detecting early neurovascular impairments.

Discrepancy between peripapillary retinal and choroidal microvasculature and the rate of localized retinal nerve fiber layer thinning in glaucoma

This observational case series study is conducted to compare the extent of microvasculature impairment in the peripapillary retina and choroid in eyes with primary open-angle glaucoma (POAG), and to investigate the association of the discrepancy between the microvasculature impairments of each layer with the rate of progressive retinal nerve fiber layer (RNFL) thinning. A total of 88 POAG eyes with a localized RNFL defect were enrolled, including 67 eyes with and 21 eyes without choroidal microvasculature dropout (CMvD). Circumferential widths of retinal microvascular impairment (RMvI) and CMvD were measured, and eyes were classified based on the relative width of CMvD to RMvI (CMvD/RMvI ratio). The rate of RNFL thinning was determined by linear regression based on ≥ 5 serial OCT examinations. Thinner global RNFL and worse visual field mean deviation at baseline were associated with a larger circumferential width of the RMvI, whereas the presence of cold extremities, lower mean arterial pressure and thinner juxtapapillary choroid were associated with a larger circumferential width of the CMvD. The rate of global RNFL thinning was faster in eyes with larger relative CMvD width than in eyes with equal CMvD and RMvI widths and in eyes without CMvD (P = 0.001). Lower mean arterial pressure (P = 0.041), larger CMvD width (P = 0.046), larger CMvD/RMvI ratio (P = 0.041), and detection of disc hemorrhage during the follow-up (P = 0.013) were significant factors associated with faster global RNFL thinning. Larger CMvD width relative to RMvI width may be indicative of an increased risk of faster RNFL thinning in POAG with localized RNFL defect. Comparing the microvasculature impairment in individual layers may help predict more rapid glaucoma progression.

Diagnostic Accuracy of Imaging Devices in Glaucoma: An Updated Meta-Analysis

Background

Different devices have diverse accuracy in diagnosing glaucoma, and therefore choosing the best device is challenging. Thereby, this study was conducted to evaluate the diagnostic sensitivity and specificity of imaging devices in glaucoma and explore the need for an updated meta-analysis on this issue.

Methods

In this systematic review and meta-analysis, PubMed, Scopus, and Web of Science databases were searched for articles published between January 2004 and 2022. Cross-sectional or diagnostic studies were selected, and sensitivity, specificity, positive predictive value, and negative predictive value were measured.

Results

A total of 28 cross-sectional studies were included for meta-analysis. Devices were divided into 2 groups, based on the optic nerve area and the macular area. For the nerve area, the pooled sensitivity was 77% (CI 95%, 70-83; I2, 90.01%) and the pooled specificity was 89% (CI 95%, 84-92, I2, 93.22%), and for the macular area, the pooled sensitivity was 87% (CI 95%, 80-92, I2, 91.79%), and the pooled specificity was 90% (CI 95%, 84-94; I2, 86.30%). We analyzed each device separately. For optical coherence tomography(OCT), the pooled sensitivity was 85% (CI 95%, 81-89; I2, 87.82%) and the pooled specificity was 89% (CI 95%, 85-92; I2, 84.39%); for Heidelberg retinal tomography (HRT), the pooled sensitivity was 72% (CI 95%, 57-83; I2, 88.94%) and the pooled specificity was 79% (CI 95%, 62-90; I2, 98.61%), and for optical coherence tomography angiography (OCTA), the pooled sensitivity was 82% (CI 95%, 66-91; I2, 93.71%) and the pooled specificity was 93% (CI 95%, 87-96; I2, 64.72%).

Conclusion

The macular area was more sensitive and specific than the optic nerve head. Furthermore, OCT had higher sensitivity, and OCTA had higher specificity when compared with other imaging devices.

Normalized Blood Flow Index in Optical Coherence Tomography Angiography Provides a Sensitive Biomarker of Early Diabetic Retinopathy

Purpose

To evaluate the sensitivity of normalized blood flow index (NBFI) for detecting early diabetic retinopathy (DR).

Methods

Optical coherence tomography angiography (OCTA) images of healthy controls, diabetic patients without DR (NoDR), and patients with mild nonproliferative DR (NPDR) were analyzed in this study. The OCTA images were centered on the fovea and covered a 6 mm × 6 mm area. Enface projections of the superficial vascular plexus (SVP) and the deep capillary plexus (DCP) were obtained for the quantitative OCTA feature analysis. Three quantitative OCTA features were examined: blood vessel density (BVD), blood flow flux (BFF), and NBFI. Each feature was calculated from both the SVP and DCP and their sensitivities to distinguish the three cohorts of the study were evaluated.

Results

The only quantitative feature capable of distinguishing all three cohorts was NBFI in the DCP image. Comparative study revealed that both BVD and BFF were able to distinguish the controls and NoDR from mild NPDR. However, neither BVD nor BFF was sensitive enough to separate NoDR from the healthy controls.

Conclusions

The NBFI has been demonstrated as a sensitive biomarker of early DR, revealing retinal blood flow abnormality better than traditional BVD and BFF. The NBFI in the DCP was verified as the most sensitive biomarker, supporting that diabetes affects the DCP earlier than SVP in DR.

Translational Relevance

NBFI provides a robust biomarker for quantitative analysis of DR-caused blood flow abnormalities, promising early detection and objective classification of DR.